action=helppanelquestionposter is an API meant for internal use by the
GrowthExperiments extension's web UI, but it has not been formally marked
as internal, so I'm announcing the recent changes  to it just in case:
- the 'email' and 'resendconfirmation' parameters have been removed;
- the 'email' response field has been removed;
- the API is now marked as internal.
The functionality provided by the API is not really useful outside of the
web-based workflow it supports, and can be approximated with other, public
APIs, so this is not expected to cause problems to any clients.